# Star

Also called: sun, named star, bright star.

A sun: a huge ball of hot gas shining by fusing hydrogen in its core. Every point of light in the night sky, apart from the planets, is one.

Stars range from red dwarfs a tenth of the Sun's mass, which can glow for trillions of years, to blue giants dozens of times heavier that burn out in a few million. Their [colour](https://astropilot.space/glossary/star-colour) shows how hot they are, and their [spectral type](https://astropilot.space/glossary/spectral-type) sorts them into families.

How bright a star looks depends on two things: how much light it gives out and how far away it is. Deneb looks fainter than Vega, yet it pours out thousands of times more light — it is about a hundred times farther away. Brightness is measured in [magnitudes](https://astropilot.space/glossary/magnitude), distance in [light-years](https://astropilot.space/glossary/light-year).

Most bright stars have proper names handed down from Arabic, Greek and Latin astronomy — Aldebaran, Betelgeuse, Sirius — and a [Bayer letter](https://astropilot.space/glossary/bayer-designation) such as α Lyrae, the brightest star of Lyra.

**At the eyepiece:** A star stays a point at any magnification: a telescope makes it brighter and its colour stronger, never bigger. Defocus a bright star a little to see its colour best.

**In AstroPilot:** Every named star has its own page: how high it climbs tonight, its colour, size and distance — and when the light you see set off.

**Examples:** [vega](https://astropilot.space/object/vega.md), [betelgeuse](https://astropilot.space/object/betelgeuse.md), [sirius](https://astropilot.space/object/sirius.md), [aldebaran](https://astropilot.space/object/aldebaran.md)

**Related:** [Star colour](https://astropilot.space/glossary/star-colour.md), [Spectral type](https://astropilot.space/glossary/spectral-type.md), [Magnitude](https://astropilot.space/glossary/magnitude.md), [Variable star](https://astropilot.space/glossary/variable-star.md), [Double star](https://astropilot.space/glossary/double-star.md), [Light-year](https://astropilot.space/glossary/light-year.md)

From the AstroPilot astronomy glossary: https://astropilot.space/glossary/star